Download or read book Wavefront Sensorless Adaptive Optics in Temporal Focusing Multiphoton Microscopy and Real time FPGA Adaptive Optics System written by and published by . This book was released on 2014 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Real time Adaptive Optic System Using FPGAs written by Steffen Mauch and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adaptive Optics Correction in Real Time for Dynamic Wavefront Errors written by Jiang Wenhan and published by . This book was released on 1990 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper reports on the principles for the use of, and the experimental results obtained from, an adaptive optics system for correcting dynamic wavefront errors in real time. The system consists of a 21-element deformable mirror, a lateral shearing interferometer, and a parallel electronic control system. Keywords: Adaptive optics; Wavefront sensing; Deformable mirror; Chinese translations. (jhd).
Download or read book Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems written by Zhizheng Wu and published by Springer Science & Business Media. This book was released on 2012-10-22 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems presents a novel design of wavefront correctors based on magnetic fluid deformable mirrors (MFDM) as well as corresponding control algorithms. The presented wavefront correctors are characterized by their linear, dynamic response. Various mirror surface shape control algorithms are presented along with experimental evaluations of the performance of the resulting adaptive optics systems. Adaptive optics (AO) systems are used in various fields of application to enhance the performance of optical systems, such as imaging, laser, free space optical communication systems, etc. This book is intended for undergraduate and graduate students, professors, engineers, scientists and researchers working on the design of adaptive optics systems and their various emerging fields of application. Zhizheng Wu is an associate professor at Shanghai University, China. Azhar Iqbal is a research associate at the University of Toronto, Canada. Foued Ben Amara is an assistant professor at the University of Toronto, Canada.
Download or read book Robust Real time Control of an Adaptive Optics System written by Steffen Mauch and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Die wissenschaftliche Arbeit trägt maßgeblich zum Verständnis der gängigen Limitierungen bei robusten echtzeitfähigen Regelungssystemen für Adaptiv Optische (AO) Systeme bei. Ein wesentlicher Teil der Arbeit befasst sich mit einer neuartigen Methode der Auswertung eines Shack-Hartmann Wellenfrontsensors (SHWFS). Die Methode basiert auf der Anwendung eines Field Programmable Gate Arrays (FPGA) zur Auswertung des SHWFS. Die zu Grunde liegende Methode ist ein Resultat der Graphentheorie zur Erkennung zusammenhängender Bildbereiche. Der Einsatz eines FPGA ermöglicht hierbei, dass die resultierende Verzögerung durch die Auswertung des SHWFS auf ein Minimum reduziert wird. Hinzu kommt, dass die neuartige Auswertungsmethode den dynamischen Bereich des Wellenfrontsensors gegenüber dem üblichen Verfahren erweitert, da für die Methode keine feste Zuordnung der Spots zu dem Linsenarray notwendig ist. Zusätzlich zu dem neuartigen Verfahren für die Auswertung wurde ein Rapid Control Prototyping (RCP) System entworfen, welches auf einem echtzeitfähigen Linux Kernel basiert. Die Echtzeitfähigkeit wird durch die Verwendung des Real-Time Application Interface for Linux (RTAI) erreicht. Der Entwurf des RCP Systems umfasst die Entwicklung spezieller Hardware wie beispielsweise eine analoge Ausgangskarte und der PCIe FPGA Framegrabber. Aus einem Simulink Modell wird automatisch C/C++ Quellcode generiert. Dieser generierte Code nutzt die vorhandenen parallelen Erweiterungen des Prozessors zur Beschleunigung der vorkommenden Berechnungen. Basierend auf diesem System wurde ein robustes Regelungsverfahren angewendet, welches auf der H_infty Entwurfsmethodik basiert. Das Entwurfverfahren des Reglers (non-smooth mu Synthese) berücksichtigt die vorhandene Unsicherheit der identifizierten Modelle bereits während der Synthese. Das Verfahren ermöglicht die H_infty Norm des geschlossenen Regelkreises zu minimieren, wobei die Regler-Struktur vorgegeben werden kann. Basierend auf verschiedenen Simulationen und experimentellen Versuchen wurde die Gültigkeit der identifizierten Modelle des AO Systems nachgewiesen. Zudem wird gezeigt, dass das entworfene RCP System deutlich leistungsfähiger als vergleichbare Systeme ist und somit eine deutlich verbesserte Performance aufweist.
Download or read book Status Go for Preclinical Imaging written by Claudia Kuntner and published by Frontiers Media SA. This book was released on 2020-12-16 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.
Download or read book The Effect of an Adaptive Optical System s Spatio Temporal Response on Imaging Performance written by and published by . This book was released on 1992 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ideally, an adaptive optical control system would have instantaneous temporal response and infinite spatial bandwidth. In real systems, the response time of the adaptive optical control system is limited by the integration time of the wave front sensor, the computational time of the control algorithm, and the actuator response time. Additionally, finite inter actuator spacing limits the deformable mirror's ability to reproduce spatial frequencies having a period less than twice this spacing. Although analyses general enough to account for both the temporal and spatial characteristics of the adaptive optical system exist, they are complex and require detailed information regarding the wave front sensor, the deformable mirror, and the control algorithm. This investigation develops a frequency domain model that describes performance effects of an adaptive optical system's temporal response taking into account aperture piston and tilt removal and spatial bandwidth limitations due to finite subaperture size. The unique aspect of this model is the relative ease with which performance characteristics of different spatial and temporal system response functions can be investigated ... Atmospheric optics, Atmospheric motion, Adaptive optics, Phase detectors, Correlation.
Download or read book Adaptive Optics and Short Wavelength Sources written by Stephen F. Jacobs and published by Addison Wesley Publishing Company. This book was released on 1978 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Linear and Non Linear Preprocessing of Wavefront Sensor Slope Measurements for Improved Adaptive Optics Performance written by Dennis Anthony Montera and published by . This book was released on 1996-03-01 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: New methods for preprocessing wavefront sensor (WFS) slope measurements are presented. Methods are developed to improve the accuracy of WFS slope measurements, as well as estimating key atmospheric and system parameters from the slope signals. Both statistical and artificial neural network solutions are investigated. Also, new atmospheric models for generating slope and phase data with the proper spatial and temporal statistics are developed. The experiments in improving the accuracy of WFS slope measurements include reducing the WFS slope measurement error and compensating for adaptive optics system time delay through temporal slope prediction. The experiments in key parameter estimation include estimating the Fried coherence length, r0, the wind speed profile, the strengths of the atmospheric turbulence layers, and the WFS mean square slope estimation error. Results of the experiments are used to make generalized conclusions in several key areas: first, the types of useful information that can be extracted from the WFS slope measurements; second, a comparison of linear or non linear methods; and third, the possibility of methods that can be developed which operate over useful ranges of seeing conditions. Overall, we find that the WFS slope measurements do contain useful information which can be extracted through various techniques. Simple transformations (either by neural network or statistical solution) on slope measurements can yield significant improvements is system accuracy without major changes to the adaptive optics system.
Download or read book Adaptive Optics at Lawrence Livermore National Laboratory written by D. T. Gavel and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics enables high resolution imaging through the atmospheric by correcting for the turbulent air's aberrations to the light waves passing through it. The Lawrence Livermore National Laboratory for a number of years has been at the forefront of applying adaptive optics technology to astronomy on the world's largest astronomical telescopes, in particular at the Keck 10-meter telescope on Mauna Kea, Hawaii. The technology includes the development of high-speed electrically driven deformable mirrors, high-speed low-noise CCD sensors, and real-time wavefront reconstruction and control hardware. Adaptive optics finds applications in many other areas where light beams pass through aberrating media and must be corrected to maintain diffraction-limited performance. We describe systems and results in astronomy, medicine (vision science), and horizontal path imaging, all active programs in our group.
Download or read book Robust and Optimal Control of an Adaptive Optics System written by Benjamin West Frazier and published by . This book was released on 2003 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics is used in optical systems requiring real-time correction of blurred images and has applications in astronomical imaging, free-space optical communications and high-energy laser beam guidance. A great deal of research has been done in optimizing the performance of adaptive optics systems, but little work has been done in analysis of the stability of these systems. This thesis outlines the design and operation of a high-speed adaptive optics system utilizing H[subscript]oo control to optimize the robust stability of the system. The system was put together using off the shelf commercial components, such as a CCD camera operating at 955 frames per second, a standard Xinetics Inc. 37 channel deformable mirror and a dual processor computer to perform computations. The system is also general purpose - it can be used in almost any application with minimal modifications and can be easily setup and operated by a minimally trained operator. The results show that the system has a dynamic range of 5 waves of focus (wavefront), an expected closed loop bandwidth of ~50 Hz and a residual error of 1/75 [lambda], rms.
Download or read book Analysis of a Sensor less Adaptive Optics System written by Reza Atashkhooei and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wavefront Control for Extreme Adaptive Optics written by and published by . This book was released on 2003 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current plans for Extreme Adaptive Optics systems place challenging requirements on wave-front control. This paper focuses on control system dynamics, wave-front sensing and wave-front correction device characteristics. It may be necessary to run an ExAO system after a slower, low-order AO system. Running two independent systems can result in very good temporal performance, provided specific design constraints are followed. The spatially-filtered wave-front sensor, which prevents aliasing and improves PSF sensitivity, is summarized. Different models of continuous and segmented deformable mirrors are studied. In a noise-free case, a piston-tip-tilt segmented MEMS device can achieve nearly equivalent performance to a continuous-sheet DM in compensating for a static phase aberration with use of spatial filtering.
Download or read book Distributed Control of a Retinal Imaging Adaptive Optics System written by Maurizio Ficocelli and published by . This book was released on 2008 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years a technique known as adaptive optics (AO), commonly used to correct the dynamic wavefront error caused by atmospheric turbulence in ground-based telescopes, has been studied as a means of correcting the dynamic wavefront error caused by aberrations in the human eye, allowing for higher resolution retinal images. In order to compensate for these dynamic aberrations, a compact AO system that tracks and compensates for these changes in real-time is needed. To realize such a system, improvements must be made in two key components, namely the control algorithms and the design of the wavefront corrector. The latter represents the main focus of this thesis. The control problem in adaptive optics systems is generalized to that of shape control for a flexible membrane representing a deformable membrane mirror used in the wavefront corrector. Due to the dynamic nature of the aberrations in the eye, the shape control problem addressed is the tracking of an unknown and time-varying shape for a distributed membrane (i.e., desired shape of the mirror). The proposed controller design approach relies on two steps. The first step is to construct a Q -parameterized set of stabilizing controllers for the system under consideration and to derive conditions on the Q parameter in the controller expression to achieve regulation. Since the desired shape of the mirror is unknown and time-varying, the second step is to derive an online tuning algorithm for the Q parameter in the expression for the parameterized stabilizing controller. The online tuning of the Q parameter allows the controller to converge to the controller needed to achieve regulation, hence compensating for the lack of information on the desired shape for the deformable mirror. Decoupling introduced in the closed loop system allows tuning to be performed using decentralized algorithms.
Download or read book Adaptive Optics for Large Telescopes written by and published by . This book was released on 1992 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High resolution Wavefront Control written by and published by . This book was released on 1999 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optimum Wavefront Sensing in Adaptive Optics Systems written by Clinton Andrew Boye and published by . This book was released on 1984 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
